Frame to support metal sheets under tension during heat treatment



u e 1 1958 M. L. HOL'SCHER ,8

V FRAME TO SUPPORT METAL SHEETS UNDER TENSION DURING HEAT TREATMENT Filed Sept. 30, 1954 4 Sheets-Sheet 1 FIG. 1. 16

M INVENTOR.

MARTIN LH L HER ATTORNEY June 17, 1958 M. L. HOLSCHER 2,839,289

FRAME TO SUPPORT METAL SHEETS UNDER TENSION DURING HEAT TREATMENT Filed Sept. 30, 1954 4 Sheets-Sheet 2 a ms.

, INVENTOR. MARTIN L E L i /D R June 17, 1958 M. L. HOLSCHER 2,839,289

FRAME TO SUPPORT METAL SHEETS UNDER 4 TENSION DURING HEAT TREATMENT Filed Sept. 50, 1954 4 Sheets-Sheet 3 FI G. 6.

' INVENTOR. MERCY 1N L fi L fifiR fiTToRNEX June 17, 1958 M. HOLSCHER v FRAME TO SUPPORT METAL SHEETS UNDER TENSION DURING HEAT TREATMENT 4 sheets-sheet 4 Filed Sept. 30, 1954 IN V EN TOR. MERL N 1'- H 1 59 3? BY A1 g w MAI-9K AT T ORNEY United brats FRAlVIE T SUPPURT METAL SHEETS UNDER TENSION DURING HEAT TREATMENT Martin L. Holscher, Opportunity, Wash., assignor to Kaiser Aluminum & Chemical Corporation, Oakland, Calif., a corporation of Delaware Application September 30, 1954, Serial No. 459,499

13 Claims. (Cl. 266-4) This invention relates to improvements in the art of heat treating metal sheets. More particularly, this invention relates to the elimination or substantial reduction of defects such as surface abrasion and wrinkling or heat treatable light metal alloy sheet, e. g., aluminum alloy sheets, during heating and quenching thereof and to a novel method and means for accomplishing the desired results.

In the production of heat treated metal sheet, e. g., 758 aluminum alloy, it is often very important to produce sheet having a smooth surface free or substantially free of abrasions. While the production of heat treated aluminum alloy sheet with such surface characteristics has always been desirable, the prior art practices often fail to achieve such results, particularly in the case of relatively large sheets.

The conventional practice for solution heat treatment of alloy sheets generally comprises suspending a plurality of sheets from a movable overhead frame by suitable means. The frame and suspended sheets are then raised into an overhead electrically heated furnace wherein large fans are used for circulating the hot air. These fans are needed to give the proper circulation of hot air in order to heat the sheets rapidly to the desired temperature and in a uniform manner. After a suitable period of heating the sheets are rapidly lowered into a quench tank located below the overhead furnace which contains a suitable liquid quenching medium for rapid cooling of the heated sheets. Such practice possesses certain inherent disadvantages with regard to abrasion and wrinkling of the sheets and which become more serious with increased sheet size. First, the air circulation produced by the fans in the overhead furnace causes the sheets to billow like sails, whereby they either bulge outwardly or bow inwardly at the center and wherein the sheets often contact one another resulting in abrasions on the surfaces thereof. Secondly, the rapidity of lowering the heated sheets into the quenching liquid results in a tendency, due to inherent buoyancy, for the sheets to be raised up. This upward movement causes further billowing of the sheets thus aggravating the abrasion problem. Moreover, the rapid quench and upward movement of the sheets often results in wrinkling of the sheets. In some cases the wrinkling is so severe that subsequent skin passes through a cold mill will not remove the wrinkles. These inherent disadvantages of prior art practice have given rise to excessive scrap losses.

Accordingly, the primary purpose and object of this invention is to provide an improved method and means for solution heat treating metal sheets which eliminates or substantially reduces many of the disadvantages of the prior art heat treating techniques.

Another object of this invention is to provide an improved method and means for solution heat treating aluminum alloy sheets which eliminates or substantially reduces the problems of surface abrasion and wrinkling.

Another object of this invention is to provide a novel means for applying tension to metal sheets.

Patented June 17, 1958 Another object of this invention is to provide a method and means for maintaining aluminum alloy sheets in tension during both the heating and quenching steps of a solution heat treating operation.

Other objects and advantages of this invention will be apparent from the following description thereof in conjunction with the accompanying drawing.

in accordance with this invention a plurality of sheets are suspended by suitable means from a movable overhead frame. The vertical edges of these sheets are fastened by suitable means to elongated flem'ble frames which are suspended from the above-mentioned overhead frame and which extend downwardly therefrom. These flexible frames are stressed within the elastic limit of the material of the flexible frame in such a manner as to exert a force away from the sheets when attached thereto. In addition,

} a means for exerting an additional force to supplement that due to the stress of the flexible frame may be applied to the flexible frame to ensure that the necessary tension will be applied to the sheets. Further, a means for spacing the lower edges of the sheets from each other may be suitably fastened to the bottom edge of each sheet as an additional aid in preventing the sheets from contacting each other during the heating and quenching steps.

The accompanying drawings illustrate a presently preferred embodiment of the tensioning and spacing means of this invention and a presently preferred method of operation.

Figure l is a fragmentary side elevational' view, partly in section, of a presently preferred embodiment of this invention and wherein a chain means of applying additional force to the flexible frame is employed.

Figure 2 illustrates the lever action chain tightening means of Figure 1 in the open rather than the closed position of Figure 1.

Figure 3 is an end elevational view of the suspended sheets and flexible frame shown in Figure 1, taken along line 33 of Figure l, with the chains removed for purposes of clarity.

Figure 4 is a perspective view of the flexible frame of this invention.

Figure 5 is a fragmentary side elevational view' of one means of clamping and suspending the sheets.

Figure 6 is an end elevational view of the means of clamping and suspending the sheets of Figure 5, taken along line 66 of Figure 5.

Figure 7 is a side elevational view of a modification of the means shown in Figure 1 wherein a jointed bracing member is substituted for the chain means of Figure 1.

Referring now more particularly to the drawings in which the same reference numerals have been applied to various corresponding parts, the present invention includes suspending each aluminum alloy sheet 1 from a suitable overhead frame 2 by means of conventional clamps 3 and hooks 4.

Overhead frame 2 may comprise two spaced side members 5 which are rigidly connected by means of suitable cross members Each cross member 6 has a series of holes 15 in the lower portion thereof. In addition, overhead frame 2 may have attached to side members S' suitable means such as an outwardly projecting flange 7 rest ing ona series. cf rollers 7' aiiixed to a stationary frame (not shown) for movably supporting overhead frame 2.

Clamps 3 and hooks 4 are more clearly shown in Figures 5 and 6. The clamps 3 generally comprise a cast body 8 having a slot 9 opening at the bottom of cast body 8, an opening 10 in open communication with slot 9 and an eye 11 formed in the upper portion 12 of clamp 3. The sheet 1 fits within slot 9'while a wedge member 13 is slidably positioned within opening 10 and has a projection 14 on one extremity thereof to prevent wedge member I 13 from coming out ofopening 10. To suspend a sheet 1 from overhead frame 2 a plurality of clamps 3 are positioned at spaced intervals along the upper edge of sheet 1. When so positioned, sheet 1 is fitted within the slot 9 of each clamp 3 and wedge member 13 is hammered in such a direction as to wedge sheet 1 within the clamp 3, by friction. Thereafter, one end of hook 4 is passed through the eye 11 of each clamp 3 while the other end of each book 4 is passed through a selected hole 15in a selected cross-member 6 of frame 2.

After the sheets have been suspended from overhead frame 2, tension is applied to the sheets bymeans of flexible frame 16 employed at each end thereof. Only one flexible frame 16 and the means for attaching same to one end of the sheets is shown in'Figuresl, 3 and 7, and a description of one will suffice for both. As shown particularly in Figure 4, each flexible frame 16 is comprised of two spaced flexible elongated rods 17 and two suitable spaced cross members, such as angle irons 19, suitably affixed to rods 17. Each angle iron 19 is provided with a plurality of holes 20 spaced along the length thereof.

The upper extremity of flexible frame 16 has hooks 18 which may be formed by curving the ends of rods 17. A short distance below hooks 18 may be provided blocks 21 which are suitably afiixed to rods 17, as by welding. While rods 17 may be of any suitable high strength flexible material, stainless steel is presently preferred. Although the rods 17, as shown in the drawings, are round in cross-section, rods of other cross-sections may be employed. It is also to be noted that although two rods and two cross members have been described in connection 'with this embodiment of the invention, that the invention is not to be limited thereto and that use can be made of less than or more than two rods and two cross members. In order to apply tension to sheets 1, each flexible frame 16 is suspended by means of the hooks 18 from one of the cross members 6 of overhead frame 2 spaced from the respective ends of sheets 1, as shown in the drawings.

IWhen so suspended, blocks 21 prevent upward movement the eye 11 of the respective clamp 3. The other extremity of each hook is passed through a selected opening in a selected angle iron 19. Hooks 4' and 4" are of insufiicient length to permit rods 17 to return to their normal position and thus a tensile force is applied to sheets 1.

Although not necessary to the satisfactory practice of the instant invention, it has been found desirable, to

ensure the necessary tension being applied to the sheets, .to providesuitable additional means for applying a force to the'fiexible frame 16. One such means is illustrated in "Figure 1 wherein chains 23 are provided for this purpose.

One or more chains may be utilized for each flexible frame In a specific embodiment of this invention, two chains 23 may be employed between an eye 24 on lower angle iron 19 of flexible frame 16 and a pair of holes 15 of a cross-member 6 on overhead frame 2 spaced from the cross member 6 from which flexible frame 16 is suspended. Hooks 22 are provided at the upper end of each chain 23 for connecting the upper end thereof to its respective hole '15 in the cross member 6. Similar hooks 25 are provided at the lower end of each chain 23 for connecting the lower end thereof to eye 24.

Where desirable, a lever action device 26 may be provided to draw chains 23 taut and thus ensure the application of a force to flexible frame 16. Device 26 comprises a metal fork-shaped member 27 having a hook 28 affixed tothe closed extremity thereof and a handle memfastened by hook 22 to a cross member 6 of frameZ.

Hook 33 is then engaged with the section of chain 23 which is attached by hook 25 to eye 24 on fleXible frame 16. By proper selection of the cross member 6 to which hook 22 will be attached, chains 23 will be loosely sus-- pended when device 26 is in the open position as indicated in Figure 2. However, by moving handle 26 to the closed position, as indicated in Figure 1, chain 23 is drawn taut thereby placing an additional force on flexible frame 16 and ensuring the application of tension to sheet 1. Itis to be understood, however, that device 26 is shown by way of example only and that means otherthan the device 26 may be employed for drawing chains 23 taut.

Another means for applying an additional force' to flexible frame member 16 is shown in Figure 7. In-accordance with Figure 7, sheets 1 are suspended from overhead frame 2 by suitable clamps 3 and hooks 4. At

each end of the sheets is a flexible frame 16 suspended from overhead frame 2 by hooks 18 and which is attached to each vertical end of sheets 1 by means of clamps 3 and hooks 4' and 4", substantially as shown and 'de scribed in connection with Figure 1. However, in order to save space and thus make use of the full length of overhead frame 2, a jointed bracing member 34 is employed on each side of flexible frame 16 and overhead frame 2. According to'this embodiment, a jointed bracing member 34 is pivotally attached by means such asa bolt 36 and a nut (not shown) to one of a series of plates 35 which in turn are affixed to frame 2. By the use of a bolt 36 and a nut (not shown) the jointed bracing member 34 may be removed from one plate 35 and attached to a different plate 35 to provide for treatment. of sheets of different lengths. The other extremity of jointed bracing member 34 is pivotally attached to the lower extremity of a rod 17 of flexible frame 16 by means such as a bolt 37 and nut (not shown). The jointed bracing member 34 consists essentially of two elongated members38 and 39 pivotally attached one to the other between the extremity.

of member 38 opposite the extremity attached to flexible frame 6 and the central portion of member 39 by a bolt 40 and nut (not shown) such that a portion of member 39 overlaps the end portion of member 38. Adjacent to bolt 40, in a direction toward bolt 37, each member 38 and 39 has a series of outwardly disposed corresponding notches 41 and 42. A ring member 43 encircles the overlapping portions of members 38 and. 39 and engages 1 a pair of corresponding notches 41 and 42. Member 39 may have a handle 44 on the extremity opposite the extremity through which bolt 36 passes. After the attachment of flexible frame 16 to the sheets through the use of hooks 4 and 4" and clamps 3, handle 44 is forced in a downward direction and ring 43'is moved in a direction away from pivot point 40 toward pivot point 37 to thereby lock members 38 and 39 in a given position and thus apply additional force on flexible frame 16.

It has also been found desirable in some instances to use a form of spacer means on the lower edge of sheets 1. This aids in preventing the sheets from coming together particularly when they are rapidly forced down into 4 pass through eyes 11 of clamps 3 and the holes of said angle irons.

It will thus be seen that the present invention provides a simple yet efiective method and means for eliminating or substantially reducing defects such as surface abrasion and wrinkling of metal sheets undergoing heat treating operations. It will be understood that although the present invention has been described with reference to the solution heat treatment of aluminum alloys, it has application to other metals, e. g. magnesium alloys, etc., where similar problems are present.

While there has been shown and described hereinabove the present preferred embodiments of this invention, it is to be understood that the invention is not limited thereto and that various changes, alterations, and modifications can be made thereto without departing from the spirit and scope thereof as defined in the appended claims wherein:

What is claimed is:

1. An apparatus for applying tension to a plurality of suspended metal sheets during treatment thereof, comprising means for suspending said sheets, an elongated flexible frame, means for supporting said frame at the upper extremity thereof in a position spaced from the ends of the said sheets, the remaining portion of said frame adapted to be stressed within the elastic limit of the material of said frame, and means for attaching said frame to the ends of said metal sheets while the frame is in said stressed condition.

2. The apparatus of claim 1 wherein means are included for exerting a force on said flexible frame to supplement that due to the stressing of said flexible frame.

3. The apparatus of claim 1 wherein spacing means are provided for attachment to the bottom edges of said sheets.

4. The apparatus of claim 1 wherein spacing means are provided for attachment to the bottom edges of said sheets and wherein means are provided for exerting a force on said flexible frame to supplement that due to the stressing of said flexible frame.

5. In apparatus for the heat treatment of metal sheets wherein said sheets are suspended in groups during heating, and rapidly lowered into a suitable quenching medium subsequent to said heating, the improvement comprising an overhead frame for supporting said sheets, means for applying tension to said sheets, said means comprising a flexible frame spaced from each of the ends of said sheets, said frames comprising at least one flexible rod having a hook means at the upper extremity thereof, and at least one cross member aflixed thereto and being provided with a plurality of spaced openings thereirnsaid flexible frame being suspended from said overhead frame by said hook means in such a manner as to maintain the portion of said rod wherein said hook is formed in a fixed position while the remaining portion of said rod can be stressed within its elastic limit in a direction toward one end of the sheets, and means for fastening said cross member to one end of the sheets utilizing said holes in said cross member and while said rod is in the stressed condition.

6. The improvement of claim 5 wherein means are provided between the lower extremity of said flexible frame and a portion of said overhead frame spaced from said flexible frame and the ends of said sheets to provide a tension force on said sheets supplementing that due to the stressing of said flexible frame.

7. The improvement of claim 5 wherein jointed bracing means are provided between the lower extremity of said flexible frame and a portion of said overhead frame spaced from said flexible frame to provide a tension force supplementing the force due to the stressing of said flexible frame, said jointed bracing means comprising two elongated members pivotally attached one to the other in a manner to provide overlapping portions of said elongated members and a locking means for encircling said overlapping portions upon actuation thereof.

8. in the heat treatment of metal sheets wherein said sheets are suspended in groups during heating, and rapidly lowered into a liquid quenching medium subsequent to said heating, the improvement comprising an overhead frame for supporting said sheets, means for applying tension to said sheets, said means including a flexible frame 5p ced from each of the ends of said sheets and comprising at least one flexible rod having a hook formed at one extremity thereof and at least one cross member ainxed thereto and being provided with a plurality of spaced openings therein, said flexible frame being suspended fro .1 said overhead frame by said hook portion of said rod in such a manner as to maintain the portion of said rod wherein said hook is formed in a fixed position while the remaining portion of said rod can be stressed within its elastic limit in the direction of the end of the sheets, means for attaching said cross member to the end of the sheets utilizing said holes in said cross member and while said rod is in the stressed condition, and spacing means for fastening to the bottom edges of said sheets.

9. The improvement of claim 8 wherein chain means are provided between the lower extremity of said flexible frame and a portion of said overhead frame spaced from said flexible frame and the ends of said sheets to provide a tension force on said sheets supplementing that due to the stressing of said flexible frame.

10. The improvement of claim 8 wherein jointed bracing means are provided between the lower extremity of said flexible frame and a portion of said overhead frame spaced from said flexible frame to provide a tension force supplementing the force due to the stressing of said flexible frame, said jointed bracing means comprising two elongated members pivotally attached together in a manner to provide overlapping portions of said elongated members and a locking means for encircling said overlapping portions upon actuation thereof.

11. A flexible frame comprising two spaced flexible rods, each rod being provided with hook means at one extremity thereof, two spaced cross members aifixed to said rods, said cross members being provided with a plurality of spaced openings therein, and block means affixed to each rod at the end portion having said hook means but spaced therefrom.

12. A flexible frame according to claim 11 wherein the cross member spaced furthest from said books is provided with eye means.

13. A flexible frame according to claim 11 wherein jointed means are provided in pivotal relationship with the lower part of said frame, said means comprising two elongated members pivotally attached together one to the other in a manner to provide overlapping portions of said elongated members and a locking means for encircling said overlapping portions and holding same in a given position, one of said elongated members being pivotally attached to the lower part of the frame at the end opposite the end which is in pivotal connection with the other elongated member.

References Cited in the file of this patent UNITED STATES PATENTS 1,366,152 August Jan. 18, 1921 1,712,988 Gann May 14, 1929 1,713,136 Leek May 14, 1929 1,924,245 Koster Aug. 29, 1933 1,939,841 Briggs Dec. 19, 1933 

